1. Field of the Invention
The present invention relates to a splice case for connecting optical fibres placed end to end or as a lateral cap from one of the fibres to the other. This case, which can be buried, including means which make available, as required, the overlength of fibre necessary for the splice to be made satisfactorily and which then, once the splice has been completed, allow this overlength to be taken up again, with the fibre then being coiled up in the case without any detrimental torsional or flexural stress.
2. Description of the Prior Art
It is known that when making a splice at the end or along the free length of an optical fibre belonging to a cable containing, inside an outer protective jacket, a plurality of such fibres, these being parallel or stranded together, requires, for various reasons, that a sufficient length of the chosen fibre be extracted from the protective jacket.
In the first instance, since the optical fibre in question is by nature fragile, it is always possible, when making the splice for connection to another fibre, that one or other of these fibres might break, requiring there still be available a long enough length to start the operation again.
Moreover, the essential steps for ensuring this fibre connection require that the lengths of fibres used are sufficient, in particular for them to be taken to a suitably equipped vehicle, situated near the place where the connection has to be made, in a chamber which is generally buried but which is situated most often at some distance from that place. By way of example, it is common practice to keep some ten meters of free fibre, or overlength, in reserve at each end of the cable.
Once the splice has been completed, the problem then arises of how to keep this overlength in reserve, making uniform turns of fibre, as a figure-of-eight or in round form, with a diameter of curvature large enough to prevent any break or cracking when bending the fibre. This operation is all the more tricky to perform the greater the relative rigidity of the cable, especially when it has to be buried.
The turns or rings of fibre thus obtained, in round form or as a figure eight, are next fixed to the wall of an inner chamber, provided beneath a case where the splice proper is made, the portions of the fibres thus housed are not, however, being protected from shocks or bending which may occur.